How do I add the ability to import Collada files to Blender 2.76?
My deleted earlier answer failed to take into account the fact that you are working from a Linux (apparently Debian) distribution. My frame of reference is on Windows, where the ability to import and export Collada files has been part of the default distribution since at least version 2.63, but I don't know that this is true with the versions for distributed by, or for, Debian. 

I note in your comment to your question an error message "This PPA does not support xenial"; a quick search of the web shows that the name "xenial" is associated with an Ubuntu Linux distribution, though I'm not sure how this affects your situation. 

If I were in your positon, I would first check with the appropriate individuals to see if the capability is been disabled in the Debian distro; if it is, then I would try uninstalling, and reinstalling Blender. If the capability is not part of the Debian version, there is an addon for Blender to import and export Collada files on Sourceforge, but I have no information as to how well it works, especially under Linux. Otherwise, if you have the skillset, you might try downloading the tarball for Blender directly from the Blender.org site and try to install Blender from there, though if you do that much work, you might as well upgrade to 2.77a.